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Different types of postmenopausal hormone therapy and mammographic density in Norwegian women
Author(s) -
Bremnes Yngve,
Ursin Giske,
Bjurstam Nils,
Lund Eiliv,
Gram Inger Torhild
Publication year - 2006
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.22437
Subject(s) - norethisterone acetate , medicine , mammographic density , breast cancer , hormone replacement therapy (female to male) , gynecology , norwegian , hormone therapy , menopause , mammography , postmenopausal women , obstetrics , oncology , cancer , demography , testosterone (patch) , linguistics , philosophy , sociology
Postmenopausal hormone therapy (HT) is associated with increased risk of breast cancer. The HTs used in Scandinavia is associated with higher risk estimates than those used in most other countries. Mammographic density is one of the strongest risk factors for breast cancer, and possibly an intermediate marker for breast cancer. We decided to examine the relationship between use of different types of HT and mammographic density in Norwegian women. Altogether, 1,007 postmenopausal participants in the governmental mammographic screening program were asked about current and previous HT use. Mammograms were classified according to percent and absolute mammographic density. Overall, current users of HT had on average 3.6% higher mean percent mammographic density when compared with never users ( p < 0.001). After adjustment for age at screening, number of children and BMI in a multivariate model, women using the continuous estradiol (E 2 ) plus norethisterone acetate (NETA) combination had a mean percent mammographic density significantly higher than never users (6.1% absolute difference). Those using the continuous E 2 plus NETA combination had an 4.8% (absolute difference) higher mean percent mammographic density after <5 years of use when compared with never users, while the corresponding number for ≥5 years of use was 7% ( p ‐trend < 0.001). We found similar associations when absolute mammographic density was used as the outcome variable. In summary, our study shows a statistical significant positive dose–response association between current use of the continuous E 2 plus NETA combination and both measures of mammographic density. © 2006 Wiley‐Liss, Inc.